The present disclosure is directed generally to thrust reversers for gas turbine engines. More specifically, the present disclosure is directed to systems for producing reverse thrust using a bypass turbofan.
Typical large bypass ratio turbofan engines utilize thrust reversers to assist aircraft in reducing speed during landing operations. Conventional thrust reversers involve interrupting the flow of bypass air generated by the turbofan with a blocker door, and rerouting the flow of that air in a forward direction to counteract forward speed of the aircraft. One such blocker door thrust reversal system is described in U.S. Pat. No. 8,109,467, which is assigned to United Technologies Corporation. Blocker door systems, however, can add upwards of 1,000 pounds (˜453.6 kg) of weight to the aircraft. Other attempts of reversing the direction of airflow generated by the fan have involved reversing the rotation of the fan itself using a clutch. One such clutch thrust reversal system is described in U.S. Pat. No. 6,148,605, which is assigned to Societe Nationale d'Etude et de Construction de Moteurs d'Aviation. However, reversing the rotational direction of the fan itself has been difficult to achieve due to the inertia of the fan system and complexity of the mechanism required to complete the reversal. There is, therefore, a need for a feasible, lightweight thrust reversal system for turbofan engines.